1. Field of the Invention
The invention relates generally to the field of digital data processing systems, and more specifically to an apparatus and method for enabling booting of an intelligent node connected to a host system.
2. Description of the Prior Art
In the past, digital data processing systems, or computers, were large and expensive systems including one or only a few central processor units connected to a main memory, mass storage such as disk and tape units, and input/output units such as printers, video display terminals, and telecommunications links. Because of the cost of such systems, they typically supported a number of users, and a significant amount of design effort went into making them faster. However, as more parts of the computers were put onto integrated circuit chips, including entire central processor units, the cost of computers declined dramatically, and so it became cost effective in many applications to devote a single computer to one or only a few users.
A benefit of having all users using a single large computer system is that data and programs may be shared among a number of users. This benefit can also be realized in an environment of smaller computers if they are linked together, for example, to form a distributed system. In a distributed system, the system is controlled by a host computer which provides services to the smaller computers, which are termed "nodes", such as data and program sharing, scheduling of resources such as printers and the like. In addition, the host assists the nodes in booting, that is, in obtaining the node's operating system programs when it (the node) initially begins operating. The operating system programs are programs which are used to control the node, including transfers to other devices in the distributed system.
Typically, when a node is initially powered up, the host senses the node being powered up and begins transferring to the node the copy of the operating system programs, that is, the "boot image", which the node will thereafter use. This is essentially a file transfer operation. However, since the node operates essentially only as a receiver, the host must perform all of the management of the transfer, decreasing its ability to do other processing work until the boot image is completely transferred.